Botary pump blade



.Fuly 26,1938. J; a. BRELSFORD ET AL 2,324,539

' ROTARY Pimn BLADE Filed Feb. 24, 19:57 2 Sheets-Sheet 1 JA MES 45. 5254 SFORD J4 y M A 0 77/ y 1938. J. a. BRELSFQR D ET AL 2,124,539

ROTARY PUMP BLADE Filed Feb. 24, 1937 2 Sheets-Sheet 2 m0 MW WM k M i 3 4, Z s ff y C 2 M W Patented July 26,1938

2,124,539 I no'mmrrUMPBn-Ann James B. Brelsford and Jay M. Roth.

' Dayton, Ohio Application February 24, 1937, Serial No. 127,501

Claims. (01. 183-136) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. Gr. 75'!) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

The present invention relates to improvements means of a sleeve 9. The inner diameter of the sleeve 9 forms what is known to the art as the inside housing bore" of the pump assembly. Ports Illa, "lb and We are cut through the sleeve 9 to provide communication with the housing 5 in rotary pumps and has for its object the provicavities 8a and 8b. sion of a rotary pump which is simple in construc- Prior to installation within the sleeve 9, a rotortiOn, y f i nt in i s perati n. blade element must be sub-assembled as follows:

n r tary pumps mployin tru circle nsid A rotor H, provided with fourequi-radiallyhousing bores, relatively thick blade is necesspaced slots I2, is held with openend up to permit 10 sary. vo v undesirable se in centrifugal loose insertion of four blades I3 and a center pin forces du h p d at n The afore- I4. An end plate I8, provided with correspondsaid centrifugal forces may be greatly decreased ing slots 2; is then secured t t open end am by using One-Piece thin blades, with him! ends rotor II by means of conventional'counter-sunk l5 protruding the rotor driving the same, but machine screws. With completion of the. above such construct ion involves limacon inside housing operation the housing 2 is next held. withjgs bores greatly increasing the manufacturing cost Open end uppermost to permit installation h of such rotary pumps- It is a further desirable foregoing sub-assembly. It will be noted that the characteristic of thin blades that they slide more blades 3 are T-shaped t b th inner extremities (bearing against the center pin I4) and outer ex- 20 t It 13 the Partlculaf 1 of Invention t0 tremlties (bearing against the inner surface of permit retention of true circle inside. housing the sleeve referred t in the claims as a cylbores and at the Same time the E blade inder). Development of the former extremity advapiases enumerated above will be dealt with in the description of Figure 3 W the foregoing and other ob ects in view, which will hereafter be referred to as a base por- 25 whlch will appear as the description e d i tion I5. The outer extremity of the blade I3 is invention consists of certain new and novel improvided with a rounded up portion l6 and l provements in rotary pump blades, which will be any overhanging portions n which ml in the hereinafter more fully illustrated in the accoms pace immediately without the periphery of the panymg drawings and more particularly pointed end plate I8 and corresponding end wall portion 30 out in the appended claims of the rotor I the outer edges overhanging por- Referring to the drawings, in which numerals of like character designate similar parts through tlons IT coming into contact with the innermost out the several claims: zgeriaicfelgf the housing 2 and the cover 3, re-

2325 z fgfi figg? View of a pump The rotor I I is turned by means of a shaft I9 35 Figure 2 is a cross-sectional view taken on the aft of flange portion pmvlded line of Figure 1 v the rlght hand extremity of the housing 2, Fig- Figure 3 a plan View f a pump incorporating ures 2 and 3. The inner bore of the end plate our invention, I8 is provided with a filler-collar 20, fixed against 40 Figure 4 S ows blade System development. rotation by means of a dowel pin 2I. The filler- In ures 1, 2, and 3, a pump assembly i i collar 20 acts as a bearing for a metering pin 22 provided with a housing 2 and housing cover 3. fixed to the housing cove 3 y means-0f a cotter Ingress and egress to the inner portion of the pin 23. An outer collar-like portion of the end housing 2 is obtained through inlet-outlets 4a. plate I8 acts as an inner. support for a ball bear- 45 and 4b. During storage or shipment, the inleting 24, recessed in the housing cover 3. A simioutlets 4a and 4b a l s d y m ans of pipe lar smaller ball bearing 25 is journaled upon the plugs 5. As shown in Figure 2, the upper right shaft I9 and finds outer support within a liner hand extremity of the housing2 is provided with 26, recessed into the housing 2'. As has been i an oil inlet 8, which during storage or shipment is stated before, a mounting flange 21 is provided 50 sealed by a pipe plug 1. The housing cover 3 is for installation of the pump assembly I upon an similarly provided with an oil inlet 6 and pipe appropriate motor device. An oil duct 28 is proplug .1. As viewed in Figure 1, the housing 2 is vlded for lubrication of the ball bearing 24, while provided with symmetrical housing cavities 8a a second oil duct 29 provides the ball bearing 25 and 8b, which are separated from one another by 55 with lubrication. Intercommunication between oil ducts 28 and 29 is provided by a third oil duct 30.

Figure 4 shows in diagrammatic form the evolution of the relatively thick blade universally employed in rotary pumps. The inner diameter of the sleeve 9 is represented by a ,circle 3|, through the center of which are passed horizontal axis X-X and vertical axis ZZ. The point of common intersection of the aforesaid axes is designated by the letter A. The outer diameter of the center pin is represented by a circle 32, which also has the axes XX and ZZpassing through the center thereof. The outer diameter of the rotor is represented by a circle 33, which ,contacts the circle 3| at the point of intersection of the vertical axis Z,-Z and the latter circle.

' While the vertical axis ZZ passes through the center of the circle 33, the horizontal axis YY passing therethrough is separated from, though parallel to, the axis X--X for the reason that the spacing of these two' axes represents the eccentricity of the rotor l2 with respect to the inner surface of the sleeve 9. Common intersection of the axes YY and ZZ are indicated by the letter B. An arc 34 is first inscribed to the left of the vertical'axis ZZ in such a manner that all points thereon will be equi-distant, radially, from the circles 3| and 32. The point of intersection of the are 34 and the axis YY has been designated by the letter C. It is now apparent that construction of radial line A-D, through the point C, will determine the point of tangencies of the arcs 36 and 31 next struck about the common center 0. Thus, to develop the minimum width of blade suitable for the eccentricity shown in Figure 4, it is necessary only that two horizon tal lines 31 and 38 be passed, respectively, through the points of tangency of the arcs 35 and 36, respectively, with the circles 3| and 32. If the rotor represented by the circle 33 be provided with four equally'spaced slots of a width sufficient to engage the sliding sides of four blades bounded by the line 31, the line 38, and those portions of the arcs 35 'and 33 lying therebetween, it is at once apparent that the center pin 2| will always be held in the central position indicated in Figure 1. However, due to excessive thickness and attendant overweight, the blades hereinabove developed will be subject to the 'serious drawbacks already discussed under the objects of our invenon. The novelty in our invention consists of selecting at random a point F in relatively close proximity to the circle 3|, Figure 4. This point we have further located on the horizontal axis YY, of the rotor |2. If a straight line A-E be erected through the point F, it is at once apparent that its intersection with circles 3| and 32 represents the points of tangency of the arcs 39 and 40, having their common center at the point F. If parallel lines 4| and 42 be erected equi-distantly from the horizontal axis YY, such that the right hand extremity of the line 42 passes through the point of tangency of the circle 3| and the are 39, the maximum required width of the outer portion of our new and improved rotor pump blade will be indicated. The inner portion of the same blade "is determined by erecting parallel and equi-distantly spaced lines 43 and 44, about the axis YY, such that the inner portion of the line 43 passes through the point of tangency of the circle 32 and the are 40. It is thus assured that the inner bearing surface of the base portion I5 will always so is substantially counterbalanced against centrifu gal forces, eliminates necessity of the center pin l4, and has in addition the freely sliding characteristic enumerated above. With the horizontal axis YY turned into coincidence with the vertical axis ZZ of Figure 4, the over-all length of the single thin blade is substantially equal to the diameter of the circle 3|. As the blade turns into coincidence with the horizontal axis YY, the outer extremities thereof are gradually and equally projected beyond the limits of the circle 3| such that their path takes the form of a limacon curve. It is at once apparent that the cost of manufacturing an"inside'housing bore of irregular curve form seriously increases the total pump cost.

Rotary pumps equipped with' our improved blades operate ma manner identical to the operation of conventional rotary pumps with the thick blade section of Figure 4. The novelty in our invention resides in reducing centrifugal forces through marked reduction in blade mass and through further improving the free sliding characteristics of ,the blades.

Although the description is specific to the illustrations in the drawings, it is to be understood that there may be numerous departures therefrom which will still be within the held and scope of the invention, so that we do not wish to be restricted thereto, but only in so far as the appended claims are so limited.

What'we claim as new is:

1. A rotary pumpcomprising a housing having a true circle inside bore, a member having a centralizing cylindrical surface disposed within said bore, a cylindrical rotor member mounted eccentrically in said here to contact the wall thereof and surround said centralizing surface, said rotor being provided with a radial slot, a one-piece blade in said rotor slot resting between the wall of said housing bore and said centralizing. surface and having convex arcuate endbearing surfaces, said blade having both of its arcuate end bearing surfaces struck from a common center, the radius of curvature of the bore bearing end being less than the radius of curvature of the centralizing surface bearing end,-the points of tangency of said convex bearing surfaces being coincident with a radial line passing through the longitudinal axis of the aforesaid housing bore and the common center of the convex surface radii, and means for establishing ingress-egress communication with said housing bore on opposite sides of the contact between said cylindrical rotor member and said housing bore.

2. A rotary pump comprising a housing having a true circle inside bore, a member having a centralizing cylindrical surface disposed within said bore, a cylindrical rotor member mounted eccentrically in said bore to contact the wall thereof and surround said centralizing surface, said rotor being provided with a radial slot, a. one-piece blade in said rotor slot resting between the wall of said housing bore and said centralizing surface '2,124,sae

and having convex arcuate end bearing surfaces, said blade having both of its arcuate end bearing surfaces struck from a common center, the radius of curvature of the bore bearing end being less than the radius of curvature of the centralizing surface bearing end, the points of tangency of said convex bearing surfaces being coincident with a radial line passing through the longitudinal axis of the aforesaid housing bore and the common center of the convexsurface radii, the thickness of the blade throughout the length of the rotor slot bearing portion thereof being substantially equal to the cord of the bearing portion of the bore bearing end of said blade and means for establishing ingress-egress communications with said housing bore on opposite sides of the contact between said cylindrical rotormember and said housing bore.

3. A rotary pump comprising a housing having a true circle inside bore, a member having a centralizing cylindrical surface disposed within said bore, a cylindrical rotor member mounted eccentrically in said bore to contact the wall thereof and surround said centralizing surface, said rotor being provided with a radial slot, a one-piece blade in said rotor slot resting between-the wall of said housing bore and said centralizing surface and having convex arcuate end bearing surfaces, said blade having both of its arcuate end bearing surfaces struck from a common center, the radius of curvature of the bore bearing end being less than the radius of curvature of the centralizing surface bearing end, the points of'tangency of said convex bearing surfaces being coincident with a radial line passing through the longitudinal axis of the aforesaid housing bore and the common center of the convex surface radii, the thickness of the blade throughout the length of the rotor slot bearing portion thereof being substaniially equal to the cord of the bearing portion of the bore bearing end of said blade and the mass distribution being such that the distance of the center of mass of the blade from the centralizing surface bearing end thereof is substantially less than one-half the blade length, and means for establishing ingress-egress communication with said housing bore on opposite sides of the contact between said cylindrical rotor member and said housing bore.

4. l A rotary pump comprising a housing having a true circle inside bore, a member having a centralizing cylindrical surface disposed within said bore, a cylindrical rotor member mounted eccentrically in said bore to contact the wall thereof and surround said centralizing surface, said rotor being provided with not less than three equally spaced radial slots, a like number of one-piece blades in said rotor slots resting between the wall of said housing bore and said centralizing surface and having convex arcuate end bearing surfaces, said blades having both of their arcute end hearing surfaces struck from a common center. the radii of curvature of the bore bearing ends of said blades being less than the radii of curvature of the centralizing surface bearing ends of saidblades, the points of tangency of each pair of convex bearing surfaces being coincident with a radial line passing through the longitudinal axis of the aforesaid housing bore and the common center of each pair of convex surface radii, and means for establishing ingress-egress communication with said housing bore on opposite sidesof the contact between said cylindrical rotor member and said housing bore.

5. A rotary pump comprising a housing having a true circle inside bore, a cylindrical center pin freely floatingly disposed within said bore, a cylindrical rotor member mounted eccentricaily in said bore to contact the wall thereof and surround said center pin, said rotor being provided with not less than three equally spaced radial slots, a like number of one-piece blades in said rotor slots resting between the walls of said housing bore and said center pin and having convex arcuate end bearing surfaces, said blades having both of their arcuate end bearing surfaces struck from a common center, the radii of curvature of the bore bearing ends of said blades being less than the radii of curvature of the center pin bearing ends of said blades, the points of tangency of each pair of convex bearing surfaces being coincident with a radial line passing through the longitudinal axis of the aforesaid housing bore and the com-, 

